Ghana striker Richmond Boakye-Yiadom continued his scoring form for Atalanta by netting the opener in their 2-0 win over Spezia on Saturday.
Bonaventura added the second as the Nerazzurri prepare for the upcoming campaign.
The on-loan player has now scored six goals in pre-season and convinced the technical team about his abilities to lead the lines when the Serie A starts ending of this month.
Boakye is yet to play a full season in the Italian top-flight after spells with Sassuolo in the Serie B.
He made two appearances for his former club Genoa including scoring on his debut at age 17.
The 21-year-old spent last season on loan at Spanish side Elche where he was the clubâ€™s top scorer in all competitions.